People who get COVID-19 despite being vaccinated against the disease could develop “super immunity” against future coronavirus infections, Oregon Health & Science University researchers have found.

“This is unusually high, unusually effective,” lead researcher Dr. Fikadu Tafesse said of his findings, published Thursday, Dec. 16 in the Journal of the American Medical Association. “You get an extremely, extremely high level of protection.”

Tafesse’s work comes nearly two years into the pandemic and as health officials and world leaders scramble to react to the latest variant of the virus, the rapidly spreading omicron. The new variant was not included in Tafesse’s study but he said he is confident the findings would apply to it, as well.

After the delta variant and low vaccination rates quashed dreams of an end to the pandemic this summer, health officials and the public have been fearful of successive waves of coronavirus variants. More troubling now, early research indicates omicron can effectively evade even vaccinated people’s immune systems and that it spreads more rapidly than the delta variant.

For one of Tafesse’s colleagues on the project, the OHSU research indicates a potential “end game” for the pandemic.

“It points to where we’re likely to land,” Dr. Marcel Curlin, associate professor of medicine and a co-author of the study, said in a statement. “Once you’re vaccinated and then exposed to the virus, you’re probably going to be reasonably well protected from future variants.”

Still, it’s unclear what concrete, practical implications the study provides, whether for the 2.7 million Oregonians and counting who are fully vaccinated or the 48,000 among them who got infected anyway.

To get his results, Tafesse, an assistant professor of molecular microbiology and immunology at the school of medicine, compared the immune system responses in blood samples collected from 52 fully vaccinated OHSU employees, 26 of whom had a breakthrough infection.

Tafesse’s lab exposed samples of the participants’ blood to live samples of five variants of the coronavirus — including delta — and measured the volume and effectiveness of the antibodies the blood generated in response.

They found a consistent pattern: The antibodies in the blood from those who had a breakthrough infection were as much as 1,000% more effective than the antibodies generated by those who had only been vaccinated.

Antibodies are one of the immune system’s key lines of defense against infection. The first viral infection — or vaccine dose — teaches the immune system what the virus looks like. When there is another exposure or infection, antibodies tailor-made for that specific virus seek out, bind to and neutralize the virus.

“Our study suggests that individuals who are vaccinated and then exposed to a breakthrough infection have super immunity,” Tafesse said.

Not only were there more antibodies in the blood of those with infections, but those antibodies were more versatile. They effectively recognized different variants as versions of the same, fundamental virus, and acted accordingly.

The reaction and pattern were so strong, Tafesse said he is confident antibodies would recognize omicron and produce a similarly robust response.

A key question Tafesse is now trying to answer is whether booster shots provide as much protection as breakthrough infections. He said he hopes to release the results of his ongoing research into that question by mid-January. Pfizer-BioNTech said last week blood from people with three doses of their vaccine produced 25 times more antibodies when exposed to the omicron variant than blood from people who got only two doses.

It’s a “very, very important” question, Tafesse said, because he would like to be able to advise the public to get booster shots. Even though he expects the two to be comparable, there’s a possibility breakthrough infections offer more protection.

Vaccines target only specific portions of the virus, meaning that if those portions mutate, an inoculated immune system might not recognize the mutated variant as the coronavirus.

A breakthrough infection, meanwhile, can teach the immune system to identify the coronavirus based on far more attributes.

“There is some advantage of being exposed to the whole virus,” even though he expects the advantage to be “minimal.”

For Tafesse, one clear message from his research is people must get their initial vaccine course in order to have a foundation of immunity.

“You have to have the vaccine first, to have this immune response,” Tafesse said.

And by no means is his research an endorsement for vaccinated people to get COVID-19.

Breakthrough infections, while mild in most cases, can still cause serious illness and death. About 2,100 Oregonians have been hospitalized with breakthrough COVID-19 infections and 580 have died. Those who died were, on average, 81 years old.

“We are not encouraging people to go get an infection,” he said.